The present invention relates to touch fasteners in general, and more specifically, to touch fasteners for incorporation by molding into molded articles.
Hook and loop type separable touch fasteners, such as those sold by the assignee of this application under the trademark Velcro, are well-known and are used to join two members detachably to each other. This type of fastener has two components. Each has a flexible substrate material having one component of the fastening system on a fastening surface thereof. One component is typically comprised of resilient hooks while the other is comprised of loops, and when the two surfaces are pressed together they interlock to form a releasable engagement.
Separable fasteners are used in the manufacture of automobile seats in the attachment of an upholstered seat cover to a polyurethane foam bun. One portion of the separable fastener is incorporated onto the surface of the polyurethane foam bun during the foam molding process. The mating portion of the separable fastener is attached to the seat cover to provide releasable attachment to the foam bun. The separable fastener assembly used in the foam mold for incorporation in the bun surface typically comprises the hooked portion of a separable fastener. This hook portion is characterized by a base carrying resilient hooks on a fastening surface. The opposite, non-fastening surface of the base may carry anchor projections to become incorporated into the foam to provide stable attachment of the separable fastener assembly to the foam article. It is also common for a backing layer or substrate to mate with the non-fastening face of the base. The substrate may be of a material that is more conducive to handling, of the component or its adherence to other articles. Anchor projections may also project from the substrate. Further, other components can be sandwiched between the substrate and the base.
A protective layer, such as a thin plastic film, may be placed over the resilient hooks, to prevent incursion of foam into the hooks during the molding process, since significant foam contamination of the hooks would affect their ability to engage with the mating portion of the fastener attached to the seat cover. Alternatively, an elastomeric cover that intimately surrounds the hooks, except for a small portion at their tips, can also be used. After the molded article is fabricated and removed from the mold, the elastomeric material is removed.
In some assemblies, a magnetically attractive shim is attached to the base to facilitate placement of the assembly in a valley (also known as a trench or trough) of the mold cavity wall, which is equipped with magnets. The shim also helps secure the hook-carrying face of the component tightly against the mold wall, thereby further minimizing incursion of the foam into the hooks. The assemblies may be referred to as xe2x80x9cmold-inxe2x80x9d fasteners or assemblies, due to their use in such molded products.
The shim can be incorporated into different locations in the assembly. It can be sandwiched between the hook carrying base and a substrate or backing layer, either temporary or permanent. It can be located centrally relative to the width of the hook-carrying base, or along its marginal edges. In cases where a thin plastic film is used to cover the hooks, the shim can be sandwiched between the plastic sheet and the hooks.
As mentioned above, it is also known to substantially cover the hook region with an elastomeric material that protects the hooks against incursion of the foam. It is known to include a magnetic attractant in this elastomeric material.
Known methods of adhering the protective film cover to the hook-carrying component include to use a long bead of hot melt adhesive there between. It is also known to include a magnetic attractant in this hot melt material.
The known methods all have drawbacks. With regard to the metal shim itself, it presents an extra component and an extra manufacturing step, thereby contributing to the cost of the assembly and the time for manufacturing a given length of material. The metal shim also contributes to the weight of the material. In the construction process, care must be taken that workers are not cut by the metal strips. The metal limits the flexibility of the strip, and consideration must be taken of the thermal expansion and contraction properties of the various binders and additional layers that might be used to secure the strip to the substrate. The metal strip also curls and bows and generally makes handling the component unwieldy.
Considering those known assemblies that use either the protective plastic or the elastomeric cover to contain the metal shim, or a magnetic attractant, there are reasons to eliminate these protective covers, if possible. The protective covers also entail additional steps, in their manufacture, attachment to the fastener assembly, and removal from the fastener assembly after molding. All protective material must be removed from the hooks (or loops, if it be the loop carrying component molded into the article), or else the hooks (or loops) will not be exposed to fasten to the mating component. These extra steps must typically be conducted away from a normal high speed production line and contribute to the cost of the fastener assembly, the time for its manufacture, and also generate a relatively large volume of essentially waste material. Additionally, sometimes a residue from the cover material remains on the fastening component after removal, which is undesirable.
Thus, there is a great need for a touch fastener assembly that can be molded into a molded product, without the use of metal shims or protective covering for the fastener components. There is also a need to simplify the manufacture of such mold-in assemblies, to minimize their cost, production time, and the time to prepare the molded product for use. It is thus an object of the invention to facilitate a simple means for providing a magnetic attractability to the mold-in fastener assembly. It is another object of the invention to provide a light weight mold-in assembly that does not require a metal shim or protective covering for the fastener components, such as hooks.
A preferred embodiment of the invention is a fastening component of a separable fastener, where some portion of the fastening component that is absolutely necessary for its fastening function, such as the hooks, the base to which the hooks are attached or a substrate that is used for another purpose, is comprised of a magnetically attractive constituent, and where another portion of the fastening component is comprised of a magnetically inert constituent. Either the hook portion or the loop portion of a typical fastener may include the magnetically attractive constituent.
A preferred embodiment of the invention is thus a component of a two component separable fastener, said component comprising a base; and carried on said base, a plurality of fastening elements; wherein at least one of said base and said fastening elements comprise a magnetically inert constituent that is intimately associated with a magnetic attractant constituent. The fastening elements and the base may be unitary, such as in the case of an extruded component, or they may be of different precursors, such as in the case of a woven fastener component.
The magnetically inert constituent may comprise a polymeric plastic or a thermoplastic elastomer, including but not limited to polypropylene, polyethylene, polyamide, polyester, polystyrene, polyvinyl chloride, acetal, acrylic, polycarbonate, polyphenylene oxide, polyurethane and polysulfone.
The magnetic attractant may impregnate the magnetically inert constituent, or it may coat or be coated by the magnetically inert constituent.
The fastening elements may comprise hook-like elements or loop-like elements.
The magnetic attractant may comprise a metal powder. The metal may be selected from the group consisting of iron powder, magnetite iron oxide, hematite iron oxide, iron(II) oxide, iron (III) oxide, iron(III) stearate. The magnetic attractant may also be an organo-iron compound or a rare earth metal.
In the case of a woven fastener, either the base structure or the hooks may include the magnetic attractant, or both may do so. Further, the material that forms the hooks may be entirely of a magnetically attractive material, with the material that forms the woven base may be magnetically inert.
The fastener may also include a substrate, that is formed from a precursor element that is separate from said base, and that is joined to said base. The fastening elements and the substrate may be coextruded or formed separately and laminated together. The substrate may be of a woven, non-woven, paper or foam material.
The fastening elements may comprise polymeric monofilaments.
Another preferred embodiment of the invention is a molded article comprising a body molded from a molding material, said body having at least one surface and an interior body region, fixed to said surface of said molded body, a separable fastener component for use with a complementary separable fastener component, said separable fastener component being according to any of the variations described above.
Another preferred embodiment of the invention is a component of a two component separable fastener, the component comprising a base and carried on the base, a plurality of fastening elements and, joined to the base, a substrate, where the substrate comprises a magnetically inert constituent that is intimately associated with a magnetic attractant constituent.
The magnetically inert constituent may be as described above, with respect to the embodiment where the magnetic attractant is associated with either the fastening elements or the base. The magnetically attractive constituent may also be any of the magnetically attractive materials identified above.
Yet another preferred embodiment of the invention is a method of making a component of a two component separable fastener, the method comprising the steps of providing a magnetic attractant and associating said magnetic attractant with at least one of a base and a plurality of fastening elements carried on said base; wherein at least one of said base and said fastening elements comprise a magnetically inert constituent that is intimately associated with said magnetic attractant.
The magnetic attractant may be associated with the base only, or the fastening elements only, or both. A polymeric plastic resin may be mixed with a magnetic attractant such as identified above. The polymeric plastic resin may be such as is identified above.
According to still another preferred embodiment, the invention is a method for making a molded article, said method comprising the steps of making a component of a two component separable fastener, such as identified above, having a magnetic attractant intimately associated therewith, according to the methods identified above. The fastening component is then placed into a mold, with its fastening face facing a wall of said mold, said mold comprising: a fastening element receiving valley region and a magnet inside a mold wall adjacent said fastening element receiving valley, whereby said magnet attracts said fastener component toward said mold wall. Molding material is provided to said mold to mold the product with the fastening component incorporated therein.